<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title>背景</title>
		<style type="text/css">
			.box{
				width: 300px;
				height: 300px;
				background-color: rgba(red, green, blue, alpha);
			}
		</style>
	</head>
	<body>
		<div class="box"></div>
	</body>
</html>
